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Home >> Infiniti >> 2021 >> QX50 Essential, FWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (DTC/Circuit Diagnosis) (4 Of 5) >> DTC/Circuit Diagnosis >> DTC P21F5: Fuel Control System B Bank 1 >> Confirmation Procedure
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Confirmation Procedure

  1. CHECK DTC PRIORITY 

    If DTC P21F5 is displayed with DTC P0172, first perform the trouble diagnosis for DTC P0172.

    Is applicable DTC detected?

    YES

    Perform diagnosis of applicable. Refer to DTC Description .

    NO

    GO TO 2.

  2. PRECONDITIONING-1 

    If DTC Confirmation Procedure has been previously conducted, always perform the following before conducting the next test.

    1. Turn ignition switch OFF and wait at least 10 seconds.
    2. Turn ignition switch ON.
    3. Turn ignition switch OFF and wait at least 10 seconds.
    NOTE: Before performing the following procedure, confirm that battery voltage is 11 V or more at idle.

    GO TO 3.

  3. PRECONDITIONING-2 
    1. Turn ignition switch ON.
    2. Clear the air fuel ratio initial learning. Refer to Work Procedure .

    Will CONSULT be used?

    YES

    GO TO 4.

    NO

    GO TO 7.

  4. PERFORM DTC CONFIRMATION PROCEDURE-1 

    SYMBOL With CONSULT

    1. Turn ignition switch ON.
    2. On CONSULT screen, select "ENGINE" >> "DATA MONITOR" >> "COOLAN TEMP/S".
    3. Start engine.
    4. Check that "COOLAN TEMP/S" indicates more than 80 deg.C (176 deg.F).

    GO TO 5.

  5. PERFORM DTC CONFIRMATION PROCEDURE-2 

    SYMBOL With CONSULT

    1. On CONSULT screen, select the following items in "DATA MONITOR".
      • ENG SPEED
      • COOLAN TEMP/S
      • B/FUEL SCHDL
      • A/F IMBALNC DIAG-CPS STAT
      • A/F IMBLNC DIAG-CPS CMPLT
    2. Drive vehicle under the following conditions for at least 20 consecutive seconds.
      CAUTION:
      • Always drive vehicle at a safe speed.
      • This procedure must be performed by two or more persons.

      ENG SPEED

      1, 400-2, 000 rpm

      COOLAN TEMP/S

      More than 80 deg.C (176 deg.F)

      B/FUEL SCHDL

      5-10 msec

      Selector lever

      D position

      A/F IMBALNC DIAG-CPS STAT

      PRSNT
      NOTE:
      • Keep the accelerator pedal as possible during cruising.
      • Drive the vehicle at approximately 88 km/h (55MPH) allows easy diagnosis.
    3. Check "A/F IMBLNC DIAG-CPS CMPLT" indication.

    Is "CMPLT" displayed?

    YES

    GO TO 6.

    NO

    GO TO 3.

  6. PERFORM DTC CONFIRMATION PROCEDURE-3 

    Check 1st trip DTC.

    Is 1st trip DTC detected?

    YES

    Proceed to Diagnosis Procedure .

    NO

    INSPECTION END

  7. PERFORM DTC CONFIRMATION PROCEDURE-4 

    SYMBOL With GST

    1. Start the engine and warm it up to normal operating temperature.
    2. Drive vehicle under the following conditions for at least 20 consecutive seconds.
      CAUTION:
      • Always drive vehicle at a safe speed.

      Engine speed

      1, 400-2, 000 rpm

      B/FUEL SCHDL

      5-10 msec

      Selector lever

      D position
      NOTE:
      • Keep the accelerator pedal as possible during crusing.
      • Drive the vehicle at approximately 88 km/h (55MPH) allows easy diagnosis.
    3. Check 1st trip DTC.

    Is 1st trip DTC detected?

    YES

    Proceed to Diagnosis Procedure .

    NO

    INSPECTION END

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